This invention relates to an apparatus for the separation of a product effluent from a fluid mixture through sequential adsorption and desorption in a single bed of adsorption particles.
Any component in a fluid mixture having adsorbate/adsorbent isotherms different from the other components in the fluid mixture can be separated from the fluid mixture, the component being attracted into the pores or onto rough surfaces of the adsorption particles. The physical adsorption of the component in the pores increases with increasing pressure and/or decreasing temperature and is reversed by lowering the pressure and/or increasing the temperature. Since adsorption is exothermic and desorption is endothermic the most efficient separation occurs if the thermal energy in the system is conserved and balanced between the two steps. However, because of the energy required to provide a thermal contribution to the separation process currently available, fluid separation such as disclosed in U.S. Pat. No. 2,944,627 only employs the use of pressure in the separation process.
The separator disclosed in U.S. Pat. No. 2,944,627 employs two beds of adsorption particles which are alternately connected to a source of fluid mixture under pressure. Adsorption takes place in one bed at an elevated pressure while the other bed is desorbed at a lower pressure. By alternating the operation of the beds, a continuous flow of product effluent is produced. However, in purging the component from the bed of adsorption particles on desorption, it is necessary to utilize up to 75 percent of the product effluent produced by the bed of adsorption particles on adsorption to effectively regenerate a bed saturated with the component. The reasons for such ineffiency are that the exothermic heat of adsorptin is displaced and not readily available to desorption; and desorption flow paths are long and highly restrictive at the desired operational pressures.
Therefore, before such fluid mixture separations are acceptable for many processes of industry, the overall efficiency thereof needs to be improved. Such an improved fluid mixture separator would be beneficial in the separation of oxygen from air to improve biological, physiological, chemical and combustion processes which use oxygen. For instance, hydrocarbon fuel use is relatively inefficient due to the incompleteness of fuel oxidation (burning) and the thermal/thermodynamic management of the burning process. It has been determined that the actual energy output of natural gas or fuel oil in heating systems or gasoline in internal combustion engines could be increased 30% or more by burning the fuels with air that is oxygen enriched.